The present invention relates to an information recording disk player, and more particularly to an information recording disk player having a video memory which is capable of storing video information for at least one field of a reproduced video signal.
A conventional apparatus of the same general type as the invention is shown in FIG. 1. In this figure, a video disk 1, which is an information recording disk, is rotatably driven by a spindle motor 2 while the information recorded on the disk is read by an optical pickup 3. The output from the pickup 3 is then amplified by a preamplifier 4, the audio component of the amplified output is demodulated by an audio demodulating circuit 5, and the resulting signal is supplied to an audio output terminal 6. The video component is demodulated by video demodulating circuit 7 and then supplied to a video output terminal 9 through a video memory (field memory or frame memory) 8. The demodulated output of video demodulating circuit 7 is also supplied to a synchronizing signal separating circuit 10 and a write clock and address generating circuit 11.
The synchronizing signal separating circuit 10 separates and extracts the horizontal synchronizing signal included in the video signal and applies it to a spindle servo circuit 12 for comparison with a reference signal produced by a reference signal generating circuit 13. The reference signal has a fixed frequency which is a multiple of a frequency determined by the applicable television system, (NTSC, etc.) standards. The spindle servo circuit 12 detects the frequency and phase difference between the recovered horizontal synchronizing signal and the reference signal and generates a servo control signal which depends on the detected frequency and phase difference. The servo control signal is used to control the driving of the spindle motor 2 through a drive circuit 14 to thus control the rotational speed of the video disk 1.
The write clock and address generating circuit 11 generates the write clock and address signal, which is used to control the write timing of video information to the video memory 8 depending on the horizontal synchronizing signal or color burst signal contained in the video signal.
The readout of video information from the video memory 8 is carried out in response to a readout clock and address signal produced by a readout clock and address generating circuit 13 on the basis of the reference signal from the reference signal generating circuit 13. Writing to the video memory 8 is enabled only when a write enable signal is supplied from an external control circuit (not illustrated) through an input terminal 16.
In such a player, the video memory 8 is capable of storing at least one field of video information. With this arrangement, jitter (time axis) variation in the reproduced video signal can be absorbed and special playing modes, such as STILL, SEARCH, SLOW, FAST, etc., can be realized in playing a CLV (Constant Linear Velocity) on which the synchronizing signal is not recorded in positions falling along a radial line on the disk. For such reproduction, writing operations from the video memory 8 are carried out with a write clock synchronized with the reproduced synchronizing signal and reading operations performed with a readout clock synchronized with the fixed-frequency reference signal.
In the conventional apparatus, these special playing modes are further realized by so-called jump operations in which the information readout point is changed by causing the pickup to jump recording tracks. Particularly, the SLOW and FAST mode playing operations are respectively realized by appropriately selecting jump points for repeated replaying of designated fields and jump points without replaying. However, it has heretobefore been impossible to reproduce the accompanying audio information in the SLOW and FAST play modes.